Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
It is often desirable to provide playback of multiple audio and/or video channels in a networked environment, for example in the context of a wireless home theater system including a plurality of wireless speaker units. For such systems, individual multimedia devices need to be synchronized, typically with the accuracy of a few microseconds. Failure to accurately synchronize devices often results in a poor user experience, and the production of unwanted playback effects.
Some synchronization techniques rely on frequency synchronizing a server and a client local clock within devices that are connected to a shared medium, with reference to a separate global clock observable by all devices coupled to that wireless network. However, wired networks typically do not have an observable global clock, as switch devices typically isolate the individual carriers to avoid collisions. Therefore these techniques are substantially isolated to topologies where the devices are connected to a shared medium. In some cases, the devices whose clocks are to be synchronized are connected by a network having different communication media. For example, one device may be connected to a network through an IEEE 802.3 based wired connection using an Ethernet interface while another device may be connected through an IEEE 802.11 based wireless LAN connection using a wireless LAN interface. These different types of communication links may have distinct transmission properties and link capacities.
There is a need in the art for improved systems and methods for synchronization in a networked environment.